feat(alarmas): surface the three native scheduling failures in Dart

Completes the bridge the native side already exposed. AlarmScheduler and
PluriWaveAlarmService record a pre-notice that could not be armed, a
refused foreground-service start, and a per-alarm reschedule that failed
after a reboot -- but nothing read them, so all three still ended at
logcat.

EstadoAlarmas now drains them at startup and turns each into a per-alarm
exception, which the card already knows how to mark. An alarm that never
reached the OS stops looking identical to one that did.

The read is deliberately tolerant: a failure to read is logged and
swallowed, never surfaced as an alarm error, so a diagnostics gap cannot
masquerade as a scheduling problem.

test/helpers/fakes_alarmas.dart

@@ -14,6 +14,7 @@ class FakePuertoAlarmasAndroid implements PuertoAlarmasAndroid {
   final soloOcultadas = <String>[];
   final ejecucionesNativas = <EjecucionAlarmaNativa>[];
   final snoozesNativos = <EstadoSnoozeNativo>[];
+  final fallosProgramacionNativos = <FalloProgramacionNativo>[];
   final _eventos = StreamController<EventoAlarmaAndroid>.broadcast();
   bool ignoraOptimizacionBateria = true;
   int solicitudesExencionBateria = 0;
@@ -186,9 +187,33 @@ class FakePuertoAlarmasAndroid implements PuertoAlarmasAndroid {
   Future<List<EstadoSnoozeNativo>> obtenerEstadoSnoozeNativo() async =>
       List.of(snoozesNativos);
 
+  @override
+  Future<List<FalloProgramacionNativo>>
+  obtenerFallosProgramacionNativos() async =>
+      List.of(fallosProgramacionNativos);
+
   int solicitudesPermisoAlarmasExactas = 0;
   int solicitudesPermisoPantallaCompleta = 0;
 
+  /// Native-recorded failures the next read should return. Tests seed this
+  /// to simulate a pre-notice that never armed, a refused foreground-service
+  /// start, or a per-alarm reschedule that failed after a reboot.
+  List<Map<String, Object?>> fallosNativos = const [];
+
+  int lecturasFallosNativos = 0;
+
+  /// Simulates an older native build with no such channel method.
+  bool fallaLecturaFallosNativos = false;
+
+  @override
+  Future<List<Map<String, Object?>>> fallosNativosProgramacion() async {
+    lecturasFallosNativos++;
+    if (fallaLecturaFallosNativos) {
+      throw StateError('canal no disponible');
+    }
+    return fallosNativos;
+  }
+
   @override
   Future<bool> solicitarPermisoAlarmasExactas() async {
     solicitudesPermisoAlarmasExactas++;